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31.
32.
B lymphocytes secreting IgG linked to latent transforming growth factor- beta prevent primary cytolytic T lymphocyte responses 总被引:3,自引:0,他引:3
B lymphocytes secreting IgG linked to latent transforming growth factor
(TGF)-beta (IgG-TGF-beta) prevent cytolytic T lymphocyte (CTL) responses to
unrelated antigens in mixed lymphocyte cultures (MLC) so long as resting
resident macrophages and functional Fc receptors are present. This was
shown using IgG-secreting plaque-forming cells (PFC) to sheep erythrocytes
(SRBC) obtained from popliteal lymph nodes of mice injected repeatedly in
foot pads with SRBC. Remarkably, as few as approximately 300 PFC prevented
CTL responses of 5 x 10(5) normal syngeneic spleen cells in MLC.
Supranatants of short-term cultures of PFC also prevented CTL responses,
and suppression was prevented by eliminating or dissociating IgG and
TGF-beta present in supranatants or by antibody against active TGF-beta.
Furthermore, the latency- associated peptide of latent TGF-beta was
detected in approximately 10% of foci of IgG captured from single PFC,
indicating that at least some B lymphocytes secrete IgG-TGF-beta as a
complex. Resting resident macrophages (which do not produce latent
TGF-beta) and functional Fc receptors were required for suppression,
consistent with idea that IgG- TGF-beta is taken up through Fc receptors
for IgG and that active TGF- beta, cleaved from latent TGF-beta of the
complex, is delivered directly to potentially responding CTL. If CTL
responses in man are similarly regulated by B lymphocytes, then an ongoing
B cell response in patients with chronic viral infections or bearing
immunogenic cancers may prevent effective therapeutic vaccination.
相似文献
33.
34.
Reciprocal effect of Waardenburg syndrome mutations on DNA binding by the Pax-3 paired domain and homeodomain 总被引:1,自引:1,他引:1
The Pax-3 protein contains two DNA-binding domains, a paired domain and a
homeodomain. Mutations in Pax-3 cause Waardenburg syndrome (WS) in humans
and the mouse Splotch (Sp) phenotype. In the Sp-delayed mouse, a mutation
in the Pax-3 paired domain (G9R) abrogates the DNA-binding activity of both
the paired domain and the homeodomain, suggesting that they may
functionally interact. To investigate this possibility further, we have
analyzed the DNA-binding properties of additional point mutants in the
Pax-3 paired domain and homeodomain that occur in WS patients (F12L, N14H,
G15S, P17L, R23L, G48A, S51F and G66D in the paired domain, V47F and R53G
in the homeodomain), the Pax-1 un mutation (G15A) and a substitution
associated with Peters' anomaly in the PAX-6 gene (R23G). Within the paired
domain, seven of 10 mutations were found to abrogate DNA-binding by the
paired domain. Remarkably, these seven mutations also affected DNA binding
by the homeodomain, causing either a complete loss (P17L and G66D), a
reduction (R23G, R23L, G15S and G15A) or an increase in DNA-binding
activity (N14H). In addition, the effect of paired domain mutations
occurred at the level of monomer formation by the homeodomain, while the
dimerization potential of this domain seemed unaffected in mutants where it
could be analyzed. Furthermore, while both homeodomain mutations were found
to abolish DNA binding by this domain, the R53G mutation also abrogated DNA
binding by the paired domain. The important observation that independent
mutations in either domain can affect DNA binding by the other in the
intact Pax- 3 protein strongly suggests that the two domains are not
functionally independent but bind DNA through cooperative interactions.
Modeling the deleterlous mutations on the three-dimensional structure of
the paired domain of Drosophila Prd shows that these mutations cluster at
the DNA interface, thus suggesting that a series of DNA contacts are
essential for DNA binding by both the paired domain and the homeodomain of
Pax-3.
相似文献
35.
Kucharczyk W; Brant-Zawadzki M; Lemme-Plaghos L; Uske A; Kjos B; Feinberg DA; Norman D 《Radiology》1985,157(1):95-101
In multiple spin-echo image sequences of blood flow, the "even-echo" phenomenon produces an absolute increase in signal magnitude from first- to second-echo images of normal vessels harboring slow flow. Distinguishing this from the apparent relatively high signal intensity seen on second-echo images in pathologic foci of stationary tissue is important to the diagnostician. Selected case material containing two tissue types was reviewed retrospectively: tissues known to harbor slow flow, such as normal veins and venous sinuses and vascular malformations, and tissues that have long transverse (T2) relaxation times and appear as intense structures on second-echo images, such as neoplasms, infarcts, and regions of demyelination. Calculations of T2 parameters were made by computer for defined regions of interest. T2 images were also generated. Visual inspection of the acquired images did not reliably distinguish increased intensity due to even-echo rephasing from the relative changes between adjacent tissues seen on second-echo images. More definitive differentiation of the even-echo phenomenon was provided by calculated values of T2 and computer-synthesized T2 images representing acquired intensity data of two-echo sequences. The synthesized images were especially useful when stationary tissue with lengthened T2 values was adjacent to or in proximity to vessels or vascular lesions. A five spin-echo image sequence was valuable for separating slow flow from stationary tissue by a technique of synthesizing T2-difference images using three consecutive echoes. 相似文献
36.
Russell EJ; Geremia GK; Johnson CE; Huckman MS; Ramsey RG; Washburn-Bleck J; Turner DA; Norusis M 《Radiology》1987,165(3):609-617
Sixteen patients with suspected cerebral metastases were studied with magnetic resonance (MR) imaging before and after the intravenous administration of 0.1 mmol/kg of gadolinium diethylenetriaminepenta-acetic acid. The images were interpreted blindly by two neuroradiologists; all clinical, radiologic (computed tomographic and MR imaging), and pathologic data were reviewed to arrive at a final "best diagnosis," which was then compared with the prior blinded interpretations. Of seven patients found to have multiple metastases, six (86%) had at least one tumor nodule depicted by postinfusion MR imaging that was missed by one or both observers on review of preinfusion images alone. Lesions missed on preinfusion studies were usually small nodules hidden by or not detected next to regions of high-signal edema thought to be related to the adjacent tumor nodule. The authors believe that contrast enhancement improves detection of metastatic foci with MR imaging and that the findings indicate broader implications for the detection of multiple lesions from other causes. 相似文献
37.
Gaskin Emily Yorga Kim Weber Berman Rebecca Allison Mandy Sheeder Jeanelle 《Maternal and child health journal》2021,25(10):1526-1553
Maternal and Child Health Journal - To describe characteristics and outcomes of Group Well-Child Care programs and provide recommendations for future research. Informed by Preferred Reporting Items... 相似文献
38.
目的:通过对骨髓单个核细胞在体外与不同细胞因子培养,了解不同细胞因子对骨髓淋巴细胞的激活能力和对骨髓干祖细胞的损伤情况。方法:将IL-1、IL-2、γ-IFN、CD3单抗进行不同组合后,在体外与骨髓单个核细胞分成对照组、IL-2组、CD3-AK、CIK组进行培养。培养过程中观察细胞形态和数量的变化,并在培养后检测免疫活性细胞的细胞毒性和造血干细胞的保存情况。结果:培养过程中对照组细胞数量减少;IL-2组细胞数量变化不明显;CD3-AK组、CIK组细胞数量显著增多,并出现较多的集聚成簇的淋巴样细胞,培养后其细胞毒性明显强于对照组及IL-2组,但细胞数量增加和细胞毒性无明性差异,培养后各组造血干细胞保存情况约16%~87%。结论:IL-2、CD3单抗在体外与骨髓单个核细胞培养后,即能激活免疫细胞增殖,又能保留足够的造血干细胞。 相似文献
39.
40.
目的 探讨人胰弹力蛋白酶Ⅰ (Humanpancreaticelastase 1 ,HPE1 )放射免疫测定 (Radioimmunoassay ,RIA)和核糖核酸酶(Ribonuclease ,RNase)活性检测的临床价值。方法 参照Satake等建立的改良HPE1RIA和Thomas等的改良酸溶性产物法检测 82例正常成年人和 2 2 2例各类患者血清并分析结果。结果 82例健康成人HPE1值为 2 3.8( 3.4ng L) ,RNase活性为 5 7.0 3( 1 2 .1 6 μ ml) ;急性胰腺炎和胰腺癌HPE1 值明显高于其他疾病 (P <0 .0 1 )。联合检测HPE1 、RNase活性可提高胰腺癌的检出率 ( 92 .47% )。结论 HPE1 RIA对急性胰腺炎有诊断价值 ,联合检测HPE1 、RNase活性检测对胰腺癌诊断有一定的临床价值 相似文献